msm: camera: core: remove extra stop during release

Don't call stop dev inside release dev since UMD call stop ioctl separately
and context state machine should decide whether stop should be called.

Change-Id: I87f7b275d38d2a6d9e901e6a16c8d5f09b1e511a
Signed-off-by: Junzhe Zou <jnzhezou@codeaurora.org>